Weekend overnights for sports telecasts were led by coverage of the NCAA men’s basketball tournament and the final round of the PGA Tour Arnold Palmer Invitational. Fox’ NASCAR Sprint Cup coverage had to air up against both events, with the Auto Club 500 earning a 3.4 overnight from 3:15-5:00pm ET. Combined with a race having to end early due to rain, that figure is down from a 4.1 rating for the race last year. The Izod IndyCar Series also began its ’12 season with the Honda Grand Prix of St. Petersburg on ABC yesterday afternoon. That figure is down from a 1.3 overnight for the same race last year. ESPN also aired Heat-Thunder last night, with the 2.4 overnight marking the net’s best NBA overnight this season to date.